JUDGMENT K. A. NAYAR, J.- What is familiarly styled as an appeal pending original petition which might have as well ended up with a direction to dispose of the appeal, pending before the appellate authority and further retraining the recovery proceedings in the meantime, on condition of the petitioner making payment of the amount directed to be paid, subjected to a detailed argument presumably because of the stake involved in the case. 2. The main prayer in the original petition is for a direction to dispose of exhibit P7 series of appeals filed against exhibit P6 series of provisional assessments for the months of April, 1990 to December, 1990 and also exhibit P8 series of stay petitions for stay of recovery of the amount covered by exhibit P6 series of provisional assessments which was demanded by exhibit P9 notice. The second prayer in the original petition is to restrain the respondents from taking recovery proceedings pursuant to exhibit P9 notice till final disposal of the appeal. The third and fourth prayers in the original petition are to restrain the first respondent, viz., Assistant Commissioner (Assessment)-I, Special Circle, Kottayam, from imposing tax on the purchase turnover of rubber in excess of 3 per cent for the years 1986-87 to 1989-90 till final decision is rendered on the appeals and other proceedings against exhibit P6 series of assessment and to restrain the first respondent from taking any further proceedings to reopen or reassess the purchase turnover of rubber used by the petitioner for the manufacture of compound rubber during the years 1982-83, 1983-84, 1984-85 and 1985-86 at more than 3 per cent. 3. The facts leadings to the petition are as follows : The petitioner is a company carrying on business of manufacturing and selling of automobile tyres, tubes and other rubber products. Its registered office is at 826, Anna Road, Madras. One of its factories is situated at Vadavathoor near Kottayam in the State of Kerala wherein it manufactures tread rubber, tubes and compound rubber according to the petitioner. For the purpose of manufacturing the above product, the petitioner purchases natural rubber from dealers and from rubber estates. Raw rubber is taxable at last purchase point in the State. One of its factories is situated at Vadavathoor near Kottayam in the State of Kerala wherein it manufactures tread rubber, tubes and compound rubber according to the petitioner. For the purpose of manufacturing the above product, the petitioner purchases natural rubber from dealers and from rubber estates. Raw rubber is taxable at last purchase point in the State. The petitioner, admittedly, being the last purchaser of the rubber within the State, was liable to pay sales tax on the turnover at 5 per cent in 1981 which was raised to 6 per cent in 1988. 4. By notification issued by the Government of Kerala in exercise of power under section 10 of the Kerala General Sales Tax Act, 1963, in the public interest, the rate of tax payable on the purchase of raw rubber by manufacturers of finished rubber products within the State, for use of such rubber by such manufacturers in the manufacture of finished rubber products within the State, was reduced from 5 per cent to 3 per cent with effect from April 1, 1981. The notification purports to extend the benefit of similar concession granted to tyre manufacturing unit as also small-scale rubber industrial unit. The petitioner submitted return in form No. 9 from 1981 onwards and in the form it is clearly mentioned that tax was paid at the concessional rate of 3 per cent on the purchase of rubber used for manufacture of tubes, tread rubber and masticated rubber within the State in the light of Notification No. S.R.O. 641/81 issued under section 10 of the Kerala General Sales Tax Act, 1963, published in the Kerala Gazette Extraordinary dated June 2, 1981 (exhibit P1). For the assessment year 1981-82, the assessing authority entertained doubt regarding the applicability of exhibit P1 notification to the purchase of raw rubber for the manufacture of compound rubber. But after hearing the petitioner's representative, the assessment was made for the year as early as on March 18, 1987, holding that "the masticated rubber produced in the factory at Vadavathoor and transferred to Madras, Arkonam and Goa is rubber compound which is a rubber product". Therefore, the officer found that the assessee is eligible for concessional rate of 3 per cent in respect of the rubber purchased for use in the manufacture of rubber products in the factory at Vadavathoor. 5. Therefore, the officer found that the assessee is eligible for concessional rate of 3 per cent in respect of the rubber purchased for use in the manufacture of rubber products in the factory at Vadavathoor. 5. Therefore, subsequent assessments were completed on that basis for the years 1982-83, 1983-84, 1984-85 and 1985-86. Those assessments have become final, for the department has not taken up the matter further in revision. While so, an explanation to exhibit P1 notification was issued by another notification dated November 2, 1990, explaining the finished rubber products for the purpose of notification to mean any goods manufactured, utilising rubber in any form as one of the raw materials and to include tread rubber but to exclude any form of rubber taxable at the point at last purchase in the State or which are subjected to processing by mixing with chemicals, gas, fumigation or any other similar process to make any compound rubber. The said notification, produced by the petitioner as exhibit P5, was deemed to have come into force on April 1, 1989, subject to the condition that taxes if any remitted by any dealer shall not be refunded. When provisional return in form No. 9 for the month of April, 1990 was submitted, the department made a departure from the earlier position and appears to have taken the view that even if rubber is used for making compound rubber inside the State, the petitioner is not entitled for concessional rate as masticated rubber produced by the company rubber is not a finished rubber product. It also took the view that the compound rubber is not a finished rubber product. Hence, by notice dated February 2, 1991, issued under section 17 read with rule 21, sub-rule (9) of the Kerala General Sales Tax Rules, the first respondent proposed to reject the return in form No. 9 claiming concessional rate of 3 per cent on the turnover of rubber purchased for the month of April, 1990. The petitioner submitted detailed reply dated March 2, 1991 to the notice issued, in which it was pointed out that the compound rubber is manufactured out of raw rubber, carbon black and chemicals and is sold to several persons as finished product. Several other manufacturing companies also, it is stated, are marketing compound rubber and, therefore, compound rubber is claimed to be a finished product. Several other manufacturing companies also, it is stated, are marketing compound rubber and, therefore, compound rubber is claimed to be a finished product. But rejecting the contention of the petitioner, provisional assessments were made denying the benefit of concession provided in exhibit P1 notice and holding that rubber compound made by mixing rubber and carbon black and transferred by the petitioner to outside States for the manufacture of tyre and tubes is not a finished product as envisaged by S.R.O. 641/1981 (exhibit P1). This provisional assessment for the month of April, 1990, is produced by the petitioner as exhibit P6. Similar assessments were made for the months of May to December, 1990, which are produced by the petitioner as exhibits P6(a) to P6(h). All these assessments were made on March 6, 1991. Final assessment for the year 1986-87 was also made immediately thereafter on March 12, 1991. Aggrieved by the provisional assessments for the months of April to December, 1990, the petitioner filed appeals, exhibits P7, P7(a) to P7(h). Along with the appeals, stay petition were also filed before the appellate authority which was marked as exhibits P8, P8(a) to P8(h). When the first respondent issued notice, exhibit P9 on May 3, 1991, to recover the entire amount due for the months of April, 1990 to December, 1990, on the basis of the provisional assessments aforementioned evidenced by exhibit P6 series, demanding an amount of Rs. 1,06,10,065 the petitioner filed this petition with the prayers already mentioned. Though final assessment was similarly made on March 12, 1991, against which also appeal was filed, the same is not subject-matter of this writ petition. 6. The main prayer is to dispose of the appeals and stay petitions as expeditiously as possible. There are also other prayers. I passed an order on May 29, 1991, granting interim stay on condition of the petitioner paying an amount of Rs. 30 lakhs within a period of one month. 7. Immediately after the provisional assessments, the first respondent also completed the final assessment for the year 1986-87 on March 12, 1991, in which the assessing officer held that the compound rubber is not a finished product and, therefore, not eligible for concession. 30 lakhs within a period of one month. 7. Immediately after the provisional assessments, the first respondent also completed the final assessment for the year 1986-87 on March 12, 1991, in which the assessing officer held that the compound rubber is not a finished product and, therefore, not eligible for concession. An appeal was filed before the Deputy Commissioner (Appeals) by the assessee which was dismissed and, thereafter the petitioner filed second appeal before the Tribunal on April 30, 1992 and that appeal is also still pending. To make the picture complete, I may add that it is stated at the Bar by counsel appearing for the petitioner, that for the years 1987-88, 1988-89 and 1989-90, assessments have not yet been completed even though annual returns were filed for the said years. 8. Appeals filed against the provisional assessments for the months of April to December, 1990, evidenced by exhibit P7 series were subsequently disposed of by the second respondent pending this original petition upholding the provisional assessment and the petitioner filed appeal against the order of the Deputy Commissioner (Appeals) before the Tribunal. Stay petitions were also filed before the Tribunal. When it was apprehended that revenue recovery proceeding will be taken, the petitioner approached this Court by way of O.P. No. 8155 of 1992. In that original petition, I directed the Sales Tax Appellate Tribunal, Additional Bench, Kottayam, to dispose of the appeal as expeditiously as possible. Since an amount of Rs. 30 lakhs, directed to be paid when the appeals were pending before the first appellate authority, had already been paid, I also directed, until disposal of the second appeals pending before the Sales Tax Appellate Tribunal, no further steps will be taken to recover the amount pursuant to exhibit P6 series. Similarly exhibit P7 series of appeals and exhibit P8 series to stay petition have already been disposed of by the second respondent. The respondents are restrained from taking recovery proceedings not only till final disposal of exhibits P7 and P8 series, but, now, by virtue of my judgment in O.P. No. 8155 of 1992, until disposal of the appeals against exhibit P6 series now pending in second appeal before the Appellate Tribunal. Therefore, the first two prayers in the original petition have already become infructuous. 9. It is seen that there are two sets of appeals pending before the Appellate Tribunal. Therefore, the first two prayers in the original petition have already become infructuous. 9. It is seen that there are two sets of appeals pending before the Appellate Tribunal. One against the assessment for the year 1986-87 and the other against the provisional assessment for the months of April to December in the year 1990-91. The petitioner filed appeals for the year 1986-87 in which the question of applicability of exhibit P1 notification to the purchase of rubber by the petitioner arose. If it is held that the petitioner purchased rubber for use by them in the manufacture of finished rubber products within the State, the petitioner will be entitled to the concessional rate of tax at 3 per cent. Admittedly, appeals will have to be disposed of on the basis of exhibit P1 notification uninfluenced by any amendment to the notification, exhibit P1, by exhibit P5 which has been brought into force only from April 1, 1989. Since the appeal is pending against the assessment for the year 1986-87 before the Tribunal, this Court will not go into the correctness of the assessment or the question whether the petitioner is entitled to be assessed at the concessional rate which are the subject-matter for decision of the appellate authority. It has been so held by this Court in Assistant Commissioner (Assessment), Sales Tax v. Duroflex Coir Industries Pvt. Ltd. [1992] 85 STC 150, Kunjahammad Haji v. State of Kerala 1960 KLT 930 , McDowell & Co. Ltd. v. Assistant Commissioner of Sales Tax [1986] 62 STC 164 and by the Supreme Court in Shamalbhai Lallubhai Patel v. Additional Special Land Acquisition Officer AIR 1977 SC 899 , Shrivastava v. Bhupendra Kumar Jain AIR 1977 SC 1703 , Bar Council of Delhi v. Surjeet Singh AIR 1980 SC 1612 , Gujarat University v. N. U. Rajguru AIR 1988 SC 66 . When the appeal is pending the appellate authority becomes vested with the legal jurisdiction of adjudicating the matter and this Court normally will not divest the appellate authority of that right in exercise of extraordinary jurisdiction. I find no exceptional or extraordinary circumstances existing in this case to justify the exercise of extraordinary power under article 226 of the Constitution of India. 10. I find no exceptional or extraordinary circumstances existing in this case to justify the exercise of extraordinary power under article 226 of the Constitution of India. 10. The question, whether the petitioner manufactured finished rubber product within the State out of the rubber purchased will have to be gone into by the Appellate Tribunal and on the said question of fact a finding has to be entered. From exhibit P2 it will be seen that the question examined in that case is whether the product of masticated rubber is rubber compound or not. It is stated therein that the masticated rubber is a mixture of raw rubber, synthetic rubber, reclaimed rubber, carbon black and other chemicals. The officer held that the masticated rubber produced in the factory of the petitioner at Vadavathoor and transferred to Madras, Arkonam and Goa is rubber compound which is a rubber product. It is on that finding for the year 1981-82 it was held that the assessee is eligible for concessional rate of 3 per cent. The Appellate Tribunal, therefore, has to enter a finding as to the nature of the product and whether the product is a finished rubber product within the meaning of Notification S.R.O. No. 641/81 (exhibit P1). This being a question of fact has to be examined by the appellate authority. Therefore, the third prayer to restrain the first respondent from assessing or imposing tax on the purchase turnover of rubber in excess of 3 per cent for the assessment years 1986-87, 1987-88, 1988-89 and 1989-90 till the final decision is rendered in the appeal and other proceedings against exhibit P6 series of assessments already made by him also cannot be granted. As stated already, assessments for the year 1986-87 has already been completed on March 12, 1991, before filing of the original petition and that is now pending before the Tribunal for final disposal. Therefore, there is no question of restraining the first respondent from assessing the petitioner for the year 1986-87. 11. Assessments for the years 1987-88 to 1989-90 have not been completed yet. The petitioner has already submitted final return and assessments had to be completed according to law. If the petitioner is aggrieved by the assessment order, if and when passed, the petitioner has adequate remedy under the Kerala General Sales Tax Act. 11. Assessments for the years 1987-88 to 1989-90 have not been completed yet. The petitioner has already submitted final return and assessments had to be completed according to law. If the petitioner is aggrieved by the assessment order, if and when passed, the petitioner has adequate remedy under the Kerala General Sales Tax Act. The petitioner will not be justified in making a prayer not to pass assessment orders for the year 1987-88 to 1989-90 till final decision is rendered against exhibit P6 series of assessment. If the petitioner is aggrieved by the final assessment for the years 1987-88 to 1989-90, it has statutory remedies under the Act and if recovery proceedings are taken, it will be open for the petitioner to approach this Court as well. Therefore, I do not find any ground to grant the prayer to restrain the respondents from assessing the petitioner in excess of 3 per cent for the assessment years 1987-88 to 1989-90 at this stage as the question is now pending, for the assessment year 1986-87, by way of appeal before the Tribunal. 12. The fourth prayer in the original petition is to restrain the first respondent from taking any further proceedings to reopen or reassess the purchase turnover of rubber used by the petitioner for the manufacture of compound rubber during the years 1982-83, 1983-84, 1984-85 and 1985-86 at more than 3 per cent. Under section 19 of the Kerala General Sales Tax Act, 1963, power is given to the Sales Tax Officers to reopen the assessment for assessment of escaped turnover wherein it is provided that where for any reason the whole or any part of the turnover of business of a dealer has escaped assessment to tax in any year or has been under-assessed or has been assessed at a rate lower than the rate at which it is assessable or any deduction has been wrongly made therefrom, the assessing authority may, at any time within four years from the expiry of the year to which the tax relates, proceed to determine to the best of its judgment the turnover which has escaped assessment to tax or has been under-assessed or has been assessed at a rate lower than the rate at which it is assessable or the deduction that has been wrongly made and assess the tax payable on such turnover. Before assessing such turnover, notice has to be given to the dealer and the dealer shall be given reasonable opportunity of being heard. Under section 35 of the Kerala General Sales Tax Act, the Deputy Commissioner has power to call and examine any order passed or proceedings recorded under the Act by any officer subordinate to him. There also no order could be passed unless the person has been given reasonable opportunity of being heard. It is mentioned in ground H of the petition that there is an attempt to reopen the assessment for the years 1982-83 to 1985-86 and that attempt is illegal, arbitrary and without jurisdiction. The question whether the exercise of power for reassessing the petitioner is arbitrary or illegal will arise only if notice is issued in that regard. The power can be exercised under section 19 or 35 of the Act. The question whether the exercise of power for reopening the assessment is valid and legal will arise only when that power is exercised. Before such power is exercised, notice will be issued when the petitioner will get an opportunity to make representation. Even though, there is no estoppel against the assessment, whether a concluded matter for the past several years can be unsettled and whether exemption given during the assessment year 1981-82 which was followed for the year 1982-83 to 1985-86 can be withdrawn without any change in the factual position for the years 1982-83 to 1985-86 will have to be considered. Perhaps, in the light of the decision reported in Radhasoami Satsang v. Commissioner of Income-tax [1992] 193 ITR 321 (SC); JT (1991) 4 SC 313 a concluded tax assessment will not be reopened ordinarily where - "......... a fundamental aspect permeating through the different assessment years has been found as a fact one way or the other and parties have allowed that position to be sustained by not challenging the order ......." But this will have to be gone into at the time when notice for reopening the assessment is issued under section 19 or 35 of the Act. It is an admitted fact, that no notice has been issued either under section 19 or under section 35. There is only a notice, exhibit P10 dated January 24, 1991, issued by the office of the Assistant Commissioner (Assessment) directing the petitioner to produce books of accounts during the years 1982-83 to 1985-86. It is an admitted fact, that no notice has been issued either under section 19 or under section 35. There is only a notice, exhibit P10 dated January 24, 1991, issued by the office of the Assistant Commissioner (Assessment) directing the petitioner to produce books of accounts during the years 1982-83 to 1985-86. Exhibit P10 is not a notice under section 19 or under section 35. The fourth prayer, therefore, to restrain the first respondent from taking any further proceedings to reopen or reassess the purchase turnover of rubber used by the petitioner for the manufacture of compound rubber during the years 1982-83 to 1985-86 at more than 3 per cent is also premature. Thus, even though the original petition will have to be dismissed on the above short grounds, Mr. Nariman, counsel for the petitioner submitted that in the light of exhibit P5 notification it has to be held that the respondents have no jurisdiction to treat compound rubber as not a finished product. Exhibit P5 is an amendment to S.R.O. No. 641/81 (exhibit P1) adding an explanation that the finished rubber products for the purpose of the said notification shall be any goods manufactured utilising rubber in any form coming under entry 161 of the First Schedule to the Act as one of the raw materials including tread rubber but excluding any form of rubber taxable at the point of last purchase in the State or which are subjected to processing by mixing with chemical, gas, fumigation or any other similar process to make any compound rubber. In short the words "finished rubber products" in exhibit P1 notification shall not include any form of rubber taxable at the last purchase point or any compound rubber which are subjected to processing by mixing with chemical, gas, fumigation or any other similar process. Since notification was dated November 2, 1990, and published in the Kerala Gazette dated November 9, 1990, it is contended that the exclusion of compound rubber from the category of finished rubber products will operate only from November 2, 1990. It is submitted that the notification cannot have retrospective effect and he referred to the decision reported in Keshavji Ravji and Co. It is submitted that the notification cannot have retrospective effect and he referred to the decision reported in Keshavji Ravji and Co. v. Commissioner of Income-tax [1990] 183 ITR 1 (SC); AIR 1991 SC 1806 , Hukam Chand v. Union of India AIR 1972 SC 2427 , Indian Express Newspapers (Bombay) P. Ltd. v. Union of India [1986] 159 ITR 856 (SC); AIR 1986 SC 515 and Bakul Cashew Co. v. Sales Tax Officer [1986] 62 STC 122 (SC) at 128. 13. Main challenge in this case is against the provisional assessments for the year 1990-91 and the assessments are now pending in appeal before the Tribunal. The amendment is only to remove the ambiguity if any. The explanation is made to remove certain ambiguities. One such ambiguity is whether the tread rubber is a finished rubber product. 14. Exhibit P5 is a notification clarifying the position. The meaning explained by the authority issuing the notification will be a good guide to explain the meaning given to finished rubber products in exhibit P1. This has been so held in Collector of Central Excise v. Andhra Sugar Ltd. [1989] 73 STC 216 (SC); JT (1988) 4 SC 410. Counsel for the respondent submitted that the purpose of the explanation evidenced by exhibit P5 was not to effect or bring about any change in law, but was intended only to clarify the law. In Keshavji Ravji and Co. v. Commissioner of Income-tax [1990] 183 ITR 1; AIR 1991 SC 1806 , the Supreme Court examined the purpose of an explanation and observed : "An 'explanation', generally speaking, is intended to explain the meaning of certain phrases and expressions contained in a statutory provision. There is no general theory as to the effect and intendment of an explanation except that the purpose and intendment of the 'explanation' are determined by its own words. An explanation, depending on its language, might supply or take away something from the contents of a provision. It is also true that an explanation may be introduced by way of abundant caution in order to clear any mental cob-webs surrounding the meaning of a statutory provision spun by interpretative errors and to place what the Legislature considers to be the true meaning beyond any controversy or doubt. It is also true that an explanation may be introduced by way of abundant caution in order to clear any mental cob-webs surrounding the meaning of a statutory provision spun by interpretative errors and to place what the Legislature considers to be the true meaning beyond any controversy or doubt. Hypothetically, that such can be the possible purpose of an 'explanation' cannot be doubted." The retrospectivity given to exhibit P5 notification with effect from April 1, 1989, perhaps may be a fact to be looked into when examining the contention of the Government Pleader that the explanation is only the exposition law or clarification of the existing law. 15. It was clarified by the amendment that tread rubber is a finished product. The retrospective effect given from April 1, 1989, subject to the condition, the tax, if any remitted by any dealer, shall not be refunded is intended to cover such person who manufactured tread rubber. If that be so, it is to be observed that a benefit has been given under the amendment and by giving retrospective effect to such a notification, the dealers are only benefited. It cannot be contended that the benefit under a notification cannot be given retrospectively. In that view of the matter retrospective effect given to the notification cannot be found fault with. But the main question is whether exhibit P1 as amended by exhibit P5 will apply to the petitioner, in respect of the appeal now pending for the year 1990-91. Since the matter is pending before the Appellate Tribunal, this Court will not consider the same in the original petition under article 226 of the Constitution of India at this stage. The purpose of explanation has been explained in the decision reported in Hira Lal Rattan Lal v. Sales Tax Officer [1973] 31 STC 178 (SC); AIR 1973 SC 1034 . Explanation cannot extend the scope of the main notification. The intention of the amendment was only to explain the main notification. It has not widened or curtailed the scope. 16. It was then contended that the scope of the main notification has to be interpreted in the light of construction given to it by the administrative authorities. The contemporary exposition of the notification by the administrative authorities is good guide for understanding the meaning. It has not widened or curtailed the scope. 16. It was then contended that the scope of the main notification has to be interpreted in the light of construction given to it by the administrative authorities. The contemporary exposition of the notification by the administrative authorities is good guide for understanding the meaning. It is contended that as will be seen from the concluded assessments for the years 1981-82 to 1985-86 which has not been taken further by the department, the authorities took the view that the compound rubber manufactured by the petitioner has to be taken as a finished rubber product within the meaning of exhibit P1 notification. Counsel for the petitioner referred to decision reported in Desh Bandhu Gupta and Co. v. Delhi Stock Exchange Association Ltd. AIR 1979 SC 1049 to contend that construction placed by administration revealed in documents issued simultaneously with the notification entitled to much weight. The principle of contemporaneo expositio (interpreting a statute or any other document by reference to the exposition it has received from contemporary authority) can be invoked, though the same will not always be decisive of the question of construction, is now well-settled. The courts, in construing a statute, will give much weight to the interpretation put upon it, at the time of its enactment by those whose duty it has been to construe, execute and apply it, though it has to controlling effect upon the court. Any such interpretation also can be disregarded for cogent and persuasive reasons. The principles have been further applied in Indian Metals & Ferro Alloys Ltd. v. Collector of Central Excise JT (1990) 4 SC 763 at para 15 and State of Madhya Pradesh v. G. S. Dall and Flour Mills [1991] 80 STC 138 (SC); JT (1990) 4 SC 430. The doctrine of contemporaneo expositio can be invoked where statutory instrument is ambiguous but is shown to have been clearly understood and explained by the administrative authorities of the law in a particular manner. A contemporaneous exposition by the administrative authorities is a very useful and relevant guide to the interpretation of the expression used in the statutory instrument. An assessment order cannot be considered exposition of the term of the notification. In any case an assessment cannot be considered a final determination of the statutory notification. 17. A contemporaneous exposition by the administrative authorities is a very useful and relevant guide to the interpretation of the expression used in the statutory instrument. An assessment order cannot be considered exposition of the term of the notification. In any case an assessment cannot be considered a final determination of the statutory notification. 17. But on a reading of exhibit P2 it will be seen that the question considered there is whether masticated rubber produced in the factory is rubber compound which is a rubber product. The question whether rubber compound itself is a finished product is not seen considered there. In any case this is a matter to be considered by the Appellate Tribunal when disposing of the appeals for the years 1986-87 and 1990-91. It is also contended that on a perusal of exhibit P5 it will be seen from the explanatory note that the explanation for finished rubber products by way of amendment was issued to remove the ambiguity and it is established principle of law that in taxation matters, if there is any ambiguity, it has to be resolved in favour of the assessee. This has been so held in Mangalore Chemicals & Fertilizers Limited v. Deputy Commissioner of Commercial Taxes [1991] 83 STC 234 (SC); JT (1992) 3 SC 482. When the question is whether a subject falls within the notification or in the exemption clause then it being in nature of exception is to be construed strictly and against the subject. Once the ambiguity or doubt about applicability is lifted and the subject falls in the notification then full play should be given to it and it calls for a wider and liberal construction. When interpreting exhibits P1 and P5 notifications, the interpretation should be given in a reasonable and purposive manner to advance the object of the notifications. [See in Bajaj Tempo Ltd. v. Commissioner of Income-tax [1992] 196 ITR 188 (SC); (1992) 3 SCC 78 and Commissioner of Income-tax v. Gwalior Rayon Silk Manufacturing Co. Ltd. [1992] 196 ITR 149 (SC); JT (1992) 3 SC 158]. 18. Counsel for the petitioner further contended that finished products should not be confused with the end-products. The finished product has been explained in the decision reported in Indian Vegetable Products Ltd. v. Union of India 1980 ELT 704. Ltd. [1992] 196 ITR 149 (SC); JT (1992) 3 SC 158]. 18. Counsel for the petitioner further contended that finished products should not be confused with the end-products. The finished product has been explained in the decision reported in Indian Vegetable Products Ltd. v. Union of India 1980 ELT 704. In that case the Bombay High Court considered the question whether the vegetable tallow manufactured from vegetable non-essential oil by hydrogenation process will be considered as excisable goods. The court held that a finished article comes into existence when it acquires distinguishable identity. By process of hydrogenation an item of vegetable tallow comes into existence and it can be identified as vegetable tallow thereafter. Therefore, when the item came into existence with the definite identity, it can be stated that the process of manufacture of vegetable tallow is completed as soon as identifiable item comes into existence. Whether such goods are used as an end-product in itself or not is wholly irrelevant. In short, merely because manufactured goods are used subsequently for manufacturing another article, it cannot be stated that the earlier manufactured goods are not finished goods. It may be that the vegetable tallow is used further for manufacture of soaps or other products. That would not make vegetable tallow as unfinished goods. Therefore, it was held that the vegetable tallow manufactured by the process of hydrogenation from vegetable non-essential oil is a finished excisable goods. In that case the court was examining the contention of the department to the effect that the manufacturer is not entitled to exemption from payment of duty on vegetable non-essential oil because the vegetable non-essential oil is used in the manufacture of finished excisable goods. The contention of the manufacturer was that the vegetable tallow is not a finished excisable goods. It is in that context the words "finished excisable goods" have been examined by the Bombay High Court. In Lakshmi Industries v. Deputy Commercial Tax Officer [1990] 77 STC 291 (Mad.), the question was whether iron and steel scrap left over in the course of manufacture of shaped and finished products by a steel re-rolling mill from raw material on which tax has been paid, comes within the definition of end-product. If it is an end-product, it is to be exempted from sales tax under a notification. If it is an end-product, it is to be exempted from sales tax under a notification. The notification provided that the raw materials out of which the end-product are manufactured if suffered tax, the end-product is exempted from tax. The question was whether the scraps which are left in the course of manufacture of shaped and finished products can be considered an end-product. The Madras High Court held that the scrap will be end-product. The decision we relied on to urge that there is a distinction between fhinish products and end-products and and all finished products need not be end-products. In the decision in Union of India v. Delhi Cloth and General Mills Co. Ltd. AIR 1963 SC 791 , the word "manufacture" has been explained in order to charge excise duty. It was held that by the process of manufacture, a new and different article having a distinctive name, character or use must be brought into existence, which ordinarily can come to the market to be bought and sold. The submission is that a new substance known to the market as rubber compound has been brought to existence and therefore, the rubber compound manufactured by he petitioner will be a finished rubber product for the purpose of exhibit P2 notification. 19. Counsel for the petitioner referred to several documents, i.e., exhibits P13, P15 and P16 to show that the compound rubber manufactured in the petitioner's factory has a separate market. But counsel fort he respondent pointed out that exhibit P13 itself produced by the petitioner shows that the sales tax has been paid on compound rubber manufactured by the petitioner under section 5(3) at the rate applicable as industrial raw material which itself will indicate that the compound rubber is not a finished product. The question whether compound rubber is a finished product or not, as stated already, is not a question of law to be examined by this Court and the same has to be considered by the final fact-finding body, the Tribunal, before whom the appeals are pending. 20. Counsel further submitted that even though notice reopening the assessment for the years 1982-83 to 1985-86 have not been issued, exhibit P10 read with the counter-affidavit filed on behalf of the first and second respondents would show that the intention of the respondents is to reopen the assessment. 20. Counsel further submitted that even though notice reopening the assessment for the years 1982-83 to 1985-86 have not been issued, exhibit P10 read with the counter-affidavit filed on behalf of the first and second respondents would show that the intention of the respondents is to reopen the assessment. Of course the averment that the assessments were made for the years 1982-83 to 1985-86 based on a false representation cannot be prima facie considered to be correct but that question may arise if there is an attempt to impose penalty. The counter-affidavit also states that what is produced by the petitioner is only masticated rubber which is not a finished rubber product. According to the respondents, it is only an intermediate product in the manufacture of tyre and tubes. The additional contention of the respondents is that the change of opinion can be a ground for reopening the assessment and it has been so held by this Court in Deputy Commissioner of Sales Tax (Law) v. T.P. Elias [1993] 90 STC 25. In what case reopening of the assessment already made can be done is laid down by the decision reported in Calcutta Discount Co. Ltd. v. Income-tax Officer AIR 1961 SC 372 at page 380; [1961] 41 ITR 191 (SC) at 207 and in Raja Bahadur Motilal Private Ltd. v. K. R. Vishwanathan, Income-tax Officer [1990] 82 CTR 381. But all these considerations will arise only when steps in this regard to reopen assessment is taken. The counter-affidavit filed in only assertive of the right to reopen, but when the power is exercised the validity will have to be questioned in appropriate proceedings. At this point of time, I do not think that I will be justified in pronouncing on the validity or otherwise of the proceedings for reassessment in contemplation of the assessing authority. 21. In Sundari Rubber Works v. State of Tripura [1991] 81 STC 200 (Gauhati), the question arose whether compound rubber is a rubber product. If it is a rubber product the same was taxable. In that case mixed compound is equated to masticated rubber and held that it is only a form of rubber and not a product of rubber. 22. In Sundari Rubber Works v. State of Tripura [1991] 81 STC 200 (Gauhati), the question arose whether compound rubber is a rubber product. If it is a rubber product the same was taxable. In that case mixed compound is equated to masticated rubber and held that it is only a form of rubber and not a product of rubber. 22. In the counter-affidavit filed on behalf of the respondents in this case, it is stated that in order to avail the concessional rate of tax, the rubber purchased within the State has to be converted into finished products. The petitioner is only subjecting the rubber purchased to certain process whereby it is converted to what is called masticated rubber according to the department and compound rubber according to the petitioner. According to the department, intermediate product is masticated rubber and, even if it is compound rubber, it will not be a finished rubber product. So the question whether the petitioner is manufacturing masticated rubber or only compound rubber and in either case whether it will be considered as finished rubber product will have to be gone into by the final fact-finding authority, the Tribunal. According to the department, the petitioner is manufacturing something within the State in between raw rubber and finished rubber product. Only for convenience of transporting or for reducing the work load in the Madras factory the raw rubber is converted into another form of rubber and it is in no way a production of a product known as such in the market. The masticated rubber or rubber compound is not known to the man in the market as a product of rubber and it has no independent use as a product according to the respondent. So the question whether the rubber compound and masticated rubber will form a rubber product and if so whether it will be a finished rubber product will have to be gone into. This has to be gone into as a question of fact applying the relevant notifications. It is not interpretation of the notification but the application of the same to the facts in question that is called for in this case. Notifications, whether it is exhibit P1 or exhibit P5, have to be read and understood according to its language. This has to be gone into as a question of fact applying the relevant notifications. It is not interpretation of the notification but the application of the same to the facts in question that is called for in this case. Notifications, whether it is exhibit P1 or exhibit P5, have to be read and understood according to its language. If the language is plain and unambiguous one must look into the language only and interpret it and give effect to the purpose of the notification. Of course, tax law has to be interpreted reasonably and in consonance with justice adopting purposive interpretation. A provision for relief shall be interpreted reasonably and in favour of the assessee. A provision in the taxing statute granting incentive for promoting growth and development should be construed liberally to advance the object of the notification. While a notification under it can be prospective or retrospective, only prospective operation can be given to a notification rescinding an exemption granted earlier. [See State of Madhya Pradesh v. G. S. Dall and Flour Mills [1991] 80 STC 138 (SC); JT (1990) 4 SC 430]. The notification is issued under section 10 of the Act in public interest. Since the exercise of power is in public interest, the court of course will require the Government to exercise the power reasonably as mandated by the decision in Associated Provincial Picture Houses Ltd. v. Wednesbury Corporation [1948] 1 KB 223. That means the authority should direct itself property and call his attention to matters which it is bound to consider and exclude from consideration irrelevant matters before exercising the discretion. The discretion for issuing notification is not unfettered. If it is arbitrary or unconstitutional or ultra vires statute, the notification will be quashed. But in this case, exhibit P1 notification is not in challenge. Even applying exhibit P1 notification for the year 1986-87, the assessing officer held that the compound rubber is not a finished rubber product and, therefore, the petitioner is eligible for concession. That matter is now pending in appeal before the Tribunal. Exhibit P1 cannot be interpreted in the light of exhibit P5 notification. It is not contended that exhibit P5 has application to the petitioner for the year 1986-87. If the position is the same before exhibit P5 is issued, no purpose will be served by interpreting exhibit P5 at this stage. Exhibit P1 cannot be interpreted in the light of exhibit P5 notification. It is not contended that exhibit P5 has application to the petitioner for the year 1986-87. If the position is the same before exhibit P5 is issued, no purpose will be served by interpreting exhibit P5 at this stage. If the petitioner is aggrieved by the decision of the Appellate Tribunal, and if it is necessary for it to raise the issue relating to the notification in a separate original petition, it can do so after availing the statutory remedy at the appropriate stage. Reserving the right to raise all the issues raised in the original petition. I dismiss the writ petition. Writ petition dismissed.